"Some of the most precious documents we possess about the Modern philosophers such as Descartes and Leibniz are the letters they wrote. To all and sundry. People who were asking them about their philosophy. Students they took on... And... I had this idea that if at some future date someone was going to collect my works, I wouldn't be embarrassed to see the letter, amongst those works..." Pathways to Philosophy: Seven Years On

Tuesday, September 20, 2011

Heidegger contra Descartes

Thank you for your email of 4 January, with your essay for the Associate Award in response to the question, ''Heidegger's notion of Dasein is not a solution to the mind-body problem posed by Descartes but a rejection of the question' - Discuss.'

This is an excellent piece of work which is fully up to the standard of the Associate award. Well done. I am glad that my selection of questions inspired you. Given that you have done so much work on this philosopher, why not tackle another?

The only issue to bear in mind is that the content of two Associate portfolio essays should not substantially overlap.

It occurred to me that John Macmurray's 'The Self as Agent' (the first of his two sets of Gifford lectures published as 'The Self as Agent' and 'Persons in Relation') makes an interesting contrast with Heidegger. Both Macmurray and Heidegger reject the Cartesian view of the self as primarily a subject of experience in favour of the self as primarily an agent in the world. However, the language is very different (Macmurray is a lot more accessible than Heidegger).

There are similarities also with the pragmatists, e.g. William James. However, it could be argued that Heidegger approaches the critique of the mind-body from a deeper analysis of the embedded subject than either Macmurray or James.

Then there is Wittgenstein's notion of the self as essentially a language user embedded 'forms of life'. I would put Wittgenstein and Heidegger on a par.

It would not be an exaggeration to say that the rejection of the 'epistemology of the passive observer' is one of the most important themes of twentieth century philosophy. (So much so, that it became one of my main interests when I started my studies as a graduate student.) The issue in expounding Heidegger is to capture what is distinctive in his particular contribution to this debate.

Your question, 'But since one entity needs no other entity in order to be. how can these two entities relate?' is based on a misunderstanding, which I do not think is Heidegger's. Descartes defines substance *per se* as an entity which is in such a way that it needs no other entity in order to be'. In other words, a mental substance, such as your soul or my soul needs no other entity in order to be, and a material substance, such as this table or the tree outside my window, needs no other entity in order to be. (By contrast, the itch in my foot or the colour of my hair cannot exist other than 'in' the substances of which they are predicated.) It was this distinction which Spinoza latched onto in rejecting the 'substances' of Descartes in favour of monism. As Descartes acknowledges, you or I exist only as a result of the continual moment-to-moment creative power of God. So, Spinoza reasoned, only God is the true substance, and everything else in the universe, whether 'mental' or 'material' is just an attribute of this one substance.

Heidegger is on strong ground in picking on Descartes' explanation (or non-explanation) of the attribute of hardness. All Descartes can say on the subject is that two extended substances cannot, for geometrical reasons, occupy the same volume of space. It was Leibniz who pointed out the serious lacuna in Descartes account of material substance in failing to give an explanation of 'impenetrability'. This connects with a defect in Cartesian physics which allows a situation which is impossible on Newtonian principles, the change of the motions of 'animal spirits' in response to an impulse from a non-material soul. - It is worth asking the question what Heidegger's analysis adds to Leibniz's critique. (I don't think you need to go into this in your essay - I am just raising this as a point of interest.)

One more general point. Much of your essay read as a Heideggerian critique of Cartesian epistemology. As such, it would work perfectly well as an answer to the question, 'Heidegger's notion of Dasein is not a solution to the problem of scepticism regarding the external world posed by Descartes but a rejection of the question' - discuss! Obviously, you are free to change the question. If you want to keep the question, then one or two signposts or reminders might save the reader from beginning to wonder, 'How is this an answer?'